Specific Absorption Rate (SAR) is a measure of the rate of radio frequency (RF) energy absorption by the body from a wireless communication device. SAR provides a straightforward means for measuring the RF exposure characteristics of wireless communication devices to ensure that they are within safety guidelines set by regulatory bodies such as the Federal Communications Commission (FCC).
In order to determine compliance, a wireless communication device is tested while operating at its highest transmit power level in all the frequency bands in which it operates, and in various specific positions against a dummy head and body, to simulate the way different users typically make use of the device. Currently, rules from most regulatory bodies require reductions in transmit power as the only means to ensure compliance.
However, reducing transmit power may result in link instability or disconnection.